Combined paperboard and plastic egg carton with self-locking cover



- T. c. BAKER 3,531,044 COMBINED PAPERBOARD AND PLASTIC EGG CARTON 1 WITH SELF-LOCKING COVER Filed March 17,- 1969 Sept. 29, 1970 I N VEN '1 0R.

THEODORE C BAKER ,4 r TORNEY United States Patent US. Cl. 229-44 9 Claims ABSTRACT OF THE DISCLOSURE This invention is directed to an egg carton having a tray provided with a plurality of depending article-receiving cells, a median horizontal ledge extending outwardly from its front and end wall, and a plurality of upwardl extending front legs having forward extending abutment shoulders. A hollow cover is hingedly connected to the rear wall of the tray and is provided along the free edge of its front wall with an inwardly folded locking flap that has its free edge engaged beneath the abutment shoulders of the tray when the cover is closed to lock same in its closed position.

This invention relates generally to new and useful improvements in cartons for packaging fragile articles and particularly seeks to provide a novel egg carton having a bottom or tray made from vacuum-formed sheet plastic and a self-locking paperboard top or cover.

My prior Pat. No. 3,346,171, which was granted on Oct. 10, 1967, is directed broadly to a combined paperboard and plastic egg carton that includes a plastic bottom and a composite plastic and paperboard cover hingedly connected thereto.

The egg carton of the present invention is an improvement thereover, particularly with respect to the means for locking the cover in its closed position.

Therefore, an object of this invention is to provide a novel egg carton having a plastic bottom or tray and a self-locking paperboard cover hingedly connected thereto.

Another object of this invention is to provide a carton of the charatcer stated in which the front wall portion of the tray includes a plurality of spaced upwardly extending legs each of which is provided at its upper end with a shallow forwardly extending abutment lug and in which the front wall of the cover is provided with an inner reverse-folded flap hingedly connected to the lower edge thereof so that the free upper edge of the flap will automatically engage the lower edges of the abutment lugs to securely lock the cover when it is moved into its carton closing position.

Another object of this invention is to provide a carton of the character stated in which the free edges of the front and end walls of the cover are supported by a horizontal ledge formed around the periphery of the tray.

Another object of this invention is to provide a carton of the character stated in which the front central portion of the horizontal ledge is configured to define a recess beneath the bottom edge of the cover when the carton is closed to enable the finger of a user to forwardly displace the front wall of the cover and progressively release the locking flap from its engagement with the abutment lugs and thus permit the cover to be lifted.

A further object of this invention is to provide a carton of the character stated in which the front portion of the horizontal ledge is provided with an upturned flange which, together with the ledge and the front faces of the upwardly extending legs, defines a U-shaped channel or trough that is adapted to receive the lower edge portion of the front wall of the cover and restrain same against forward displacement when the cover is closed.

3,531,044 Patented Sept. 29, 1970 A further object of this invention is to provide a carton of the character stated that is simple in design, rugged in construction and economical to manufacture.

With these and other objects, the nature of which will be apparent, the invention will be more fully understood by reference to the drawing, the accompanying detailed description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a front elevation, partly in section, of a carton constructed in accordance with this invention;

FIG. 2 is a vertical transverse section taken along line 2-2 of FIG. 1 and shows the cover in a partly closed position;

FIG. 3 is a view similar to FIG. 2, but shows the cover in its closed and locked position; and

FIG. 4 is an enlarged detailed vertical transverse section taken along line 4-4 of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing in detail the invention, as illustrated, is embodied in a one dozen egg carton that includes a bottom or tray, generally indicated 5, formed from a suitable sheet plastic maerial and a top or cover, generally indicated 6, preferably formed from paperboard.

The tray 5 may be vacuum or pressure formed from sheet polystyrene, or other suitable plastic, to define two spaced parallel rows of depending egg-retaining cells 7, a plurality of upstanding spaced center posts '8, a plurality of upstanding front legs 9 aligned with the center posts 8, a plurality of upstanding rear legs 10 aligned with the center posts 8, and four corner shoulders 11.

A median horizontal ledge 12 extends outwardly from the front and end walls of the tray and is provided along its front wall portion with an upstanding lip or flange 13 which, together with the ledge 12 and the front faces of the legs 9, defines a trough or channel for receiving and retaining the lower edge of the front wall of the cover 6.

The center of the front ledge 12 is deformed downwardly as at 14 to define a finger-access cavity 15 and the flange 13 is discontinuous for a short distance on each side of the cavity 15, also for finger-access purposes.

The rear legs 10 collectively include a continuous upstanding rear wall 16 which hingedly supports the cover 6.

The front legs 9 each includes a rearwardly sloping front wall portion 17 terminating at its upper end in a forwardly projecting lug 18 provided on its lower portion with a horizontal abutment shoulder 19 adapted to be engaged by the free edge of a cover locking flap as will be hereinafter more fully described.

The cover 6 preferably is fabricated from coated or uncoated bleached sulfate paperboard in the form of a frustum of a rectangular pyramid and includes a rectan gular top 20, trapezoidal end walls 21, 21, a trapezoidal rear wall 22 provided at its lower edge with a hinge flap 23 that is adhesively or otherwise secured to the rear face of the tray wall 16, and a trapezoidal front wall 24 provided at its lower edge with looking flap 25 hingedly connected thereto and reverse folded into proximity with the rear or inner face of the front wall.

The locking flap 25 is sufliciently long to span the full distance of the front legs 9 and has a height substantially equal to the distance from the upper face of the ledge 12 to the abutment shoulders 19 of the front legs. The height of the cover 6 is such that when it is closed over the tray 5, the top wall 20 will be supported by the center posts 8 and thus prevent the contained eggs from becoming vertically crushed either during handling of an indi vidual carton or when the cartons are vertically stacked.

After the tray 5 is filled with eggs the cover 6 is simply swung into its closure-forming position thereover so that the locking flap 25 will slide downwardly across the faces of the lugs 18 until the free bottom edges of the cover walls become seated on the ledge 12, at which time the free upper edge of the locking flap 25 will spring rearwardly a slight distance and become engaged with the abutment shoulders 19 of the front legs 9 to securely lock the cover in its closed position.

The cover is prevented from diagonal warping when in its closed position as the result of the engagement of its lower corners over the corner shoulders 11, and its front wall 24 is prevented from accidental forward bulging because its lower edge rests behind the upstanding flange 13.

The closed carton may be opened deliberately simply by inserting a thumb or finger in the cavity 15 beneath the edge of the cover and pulling the central front wall portion outwardly and upwardly against the flexing resistance of the flange 13. This will also cause the locking flap 25 to pivot about its free edge as a fulcrum against the abutment shoulders 19 and force relative movement to take place between the front wall of the cover, portions of the locking flap and the upper portions of the front legs 9 to effect complete release of the cover so that it can then be swung about its hinge flap 23 to its fully open position.

It will be understood that although the exact height of the locking fiap 25 is not critical, it must not be so high that ready opening of the top would be prevented as the result of a too long lever arm represented by the height of the flap.

What is claimed is:

1. A carton including a tray having front, rear and end walls, a horizontal ledge extending outwardly from said front wall, a front leg positioned behind said ledge and extending upwardly therefrom, the upper portion of said leg being provided with a forwardly extending abutment shoulder, a hollow cover open at the bottom and hingedly connected to the rear wall of said tray, said cover including a top panel, a pair of end walls, and a front wall having its free lower edge supported by said horizontal ledge, said cover front wall being provided at its lower edge with an inner reverse-folded flap hingedly connected thereto in alignment with said front leg, said flap having a height substantially equal to the distance from the upper surface of said ledge to the under surface of said abutment shoulder whereby to permit the free upper edge of said flap to become engaged beneath said abutment shoulder when said cover is closed to lock same in its closed position.

2. The carton of claim 1 wherein the horizontal ledge also extends outwardly from the tray end walls and the free lower edge portions of the cover end walls are supported by the tray end wall portions of the horizontal ledge.

3. The carton of claim 1 additionally including a plurality of said front legs and abutment shoulders arranged in spaced relation along the front of said tray, said reverse-folded flap having a width sufiicient that its free edge simultaneously will engage all of said abutment shoulders.

4. The carton of claim 3 additionally including a flange extending upwardly from the front edge of said horizontal ledge.

5. The carton of claim 3 in which the central portion of said horizontal ledge is deformed downwardly to define a finger-access cavity.

6. The carton of claim 4 in which the central portion of said flange is discontinuous and in which the central portion of said horizontal ledge is deformed downwardly to define a finger-access cavity.

7. The carton of claim 3 in which said tray is provided with a plurality of depending article-receiving cells.

8. The carton of claim 5 in which said tray is provided with a plurality of depending article-receiving cells.

9. The carton of claim 6 in which said tray is provided with a plurality of depending article-receiving cells.

References Cited UNITED STATES PATENTS 2,804,251 8/ 1957 Millett 2292.5 3,163,345 12/ 1964 Schwertfeger.

3,346,171 10/1967 Baker 22944 3,356,284 12/1967 Lake 2292.5 3,459,360 8/ 1969 Bagay 22944 DAVIS T. MOORHEAD, Primary Examiner US. Cl. X.R. 

